Mechanical and tribological properties of carbon fiber-reinforced polyetheretherketone composite coatings by flame-spraying method

The carbon fiber-reinforced polyetheretherketone (CF/PEEK) composite coatings with two types of short CFs, that is, 300- and 600-mesh, each in the contents of 10 and 30 wt% are deposited in comparison with the pure PEEK coatings by using a flame spraying method, respectively. The 300-mesh CFs with intact morphology and the 600-mesh CFs preserving fractured shape and higher graphitization degree are selected as the reinforced fillers in the CF/PEEK composite coatings. The flame-sprayed CF/PEEK composite coatings show the increased porosity with the higher CF contents. The adding of CFs in the flame-sprayed CF/PEEK composite coatings limits the thermal degradation of PEEK and restrains the PEEK crystallization showing low crystallinity degree and small crystallite size. The composite coatings in 10 wt% CF content exhibit the optimized nanoindentation behavior and tribological property. The 300-mesh CFs with large length and intact morphology in flame-sprayed CF/PEEK composite coatings lead to the increased surface hardness by 1.31 times over that of the pure PEEK coatings. The 600-mesh CFs with higher graphitization degree contribute to better tribological property of flame-sprayed CF/PEEK composite coatings with an order of magnitude lower specific wear rate.